That won't work because I'm not redirecting traffic from an old page to a new page. I want to redirect all traffic coming from a specific domain to a different page than the url they are sending traffic to.

Some site is linking to my index.php page, but they should be using a different url (differenturl.php) and I can't get in contact with them to get it changed. I only want to redirect traffic coming from one specific domain.

yes, that's pretty much it... use the %{referer} part to identify where its coming from and the %{query_string} to determine what it is that's being asked for... both are rewritecond's and then followed by the rewriterule... please also verify the correct terms vis a vis %{referer} and %{query_string}... also note that CaPitaLiZation is important with regard to the commands... you can use [NC] after each of the rewritecond's to make then NoCase sensitive... that way INDEX.php will match index.php and such...

also remember, if you already have a .htaccess file, back it up first so that if something goes wonky on ya, you can put it back in place and start again...

Note that i have replaced "/otherurl.php" with "http://example.com/otherurl.php" (the full URL). The problem is that a R=301 is an external redirect, that means that internal URL's cannot be used as replacement URLs. That is: "example.com" is your own domain name, use "www." in front of it if you normally do so.

I'm learning something new everday, so maybe one of these days I'll be back here giving back some of the stuff I've learned. I've been doing the "webmaster" thing for 2 years and I'm amazed at how much I don't know and how much more there is to learn.

Since adding that redirect to the htaccess I've noticed this in the error logs

Options FollowSymLinks or SymLinksIfOwnerMatch is off which implies that RewriteRule directive is forbidden: /home/virtual/site10/fst/var/www/html/_vti_bin/owssvr.dll

I've also noticed that not everyone that comes from the domain the traffic is being redirected from is getting redirected. That's ok though cause it's only 1 every 5 mins or so and I'm not really concerned about it.

If not, then maybe the request is not encountering the Option +FollowSymLinks directive in the code posted above.

If some requests are getting through, it is likely that we've missed a detail in the HTTP_REFERER or the requested URI. That is, the referer and requested file must match exactly as specified in the rules in order for the rewrite to work.